A production process of a toner (hereinafter may also be referred to as “a toner” merely) for electrostatic image development according to a chemical process has such advantages that energy required for production is small, the particle size of the resulting toner can be made small, and occurrence of a finely powdered component can be inhibited.
Especially, an emulsification aggregation process is a process in which a dispersion of fine binder resin particles formed of a binder resin prepared by emulsion polymerization or the like is mixed with a dispersion of other toner particle forming components such as fine colorant particles as needed, an aggregating agent is added, thereby aggregating these particles, an aggregation stopper is added, as needed, to control particle size of the aggregated particles, and the shape of the particles is further controlled by fusion bonding, thereby producing toner particles.
A process of utilizing polysilicato-iron, which is an inorganic polymer, as the aggregating agent in this emulsification aggregation process is disclosed (see Patent Literature 1).
When polysilicato-iron is used as the aggregating agent, desired toner particles can be obtained with a small amount of the aggregating agent because the polysilicato-iron is a compound comprising iron and silica as main components, and so a charge-neutralizing reaction by an iron salt and a crosslinking action by polymerized silicic acid are caused.
In the process disclosed in the Patent Literature 1, however, an alkali compound is used as the aggregation stopper. Since a sufficient aggregation-relaxing effect is not achieved by adding such an alkali compound, there is a problem that difficulties are encountered on the control of a particle size and the sharpening of a particle size distribution of the resulting toner.